Application of electron spin resonance spectroscopy in detection of irradiated grapes

In order to detect irradiated grapes by electron spin resonance（ESR）spectroscopy, the grape skins, grape stalks and grape seeds were used as test materials to study the feature changes of ESR spectrum and the relationship between ESR intensity and irradiation dose in the range of 0 to 10 kGy. The results showed that the ESR spectra of grape skins, grape stalks and grape seeds were obviously different before and after irradiation, the intensity of ESR signal increased with the increasing of the absorbed dose. The grape stalks which had the minimum detection limit (0.25 kGy) could be used as an ideal experimental material to identify whether or not grapes had been irradiated. By comparing the dose effect curves of grape skins, grape stalks and grape seeds, it was concluded that grape stalk curves showed the most accurate (R2=0.9943). The ESR intensity of three kinds of irradiated samples all decreased during the storage time (15 d), grape skins showed severest attenuation (attenuation 80%). The results could provide the technical basis for the application of ESR spectroscopy in detecting irradiated grapes.